Improvement in hot-air furnaces



`V Sheets--Sheet L W. H. `L'I'Z.

Hot-Air Furnaces.

No 153 Q03, Patented Au'gJIJBM.

"z-H- 00000 C MG@ 0000 --hz/ PATENT OFFICE.

WILLIAM H. LOTZ, 0F CHICAGO, ILLINOIS.

IMPROVEMENT IN HOT-AIR FURNACES.

Specification forming part of Letters Patent No. 153,903, dated August 11, 1874; application iiled March ll, 1874.

To all whom it may concern:

Be it known that I, WILLIAM H. LOTZ, of Chicago, in the county of Cook and State of Illinois, have invented an Improvement `in Hot-Air Furnaces, of which the following is a specification The first part of my invention relates to an improvement in the fire-pot and combustionchamber of a stove 0r furnace, whereby more perfect combustion of the gases evolved from the fuel can be secured. The second part of my invention relates to a pair of air-registers in the base-chamber, both simultaneously actuated by a single lever in such a manner that the inuent current of fresh air may be drawn at will either from the external atmosphere, or, during very cold weather, from the apartment in which the furnace is placed. The third part of my invention relates to the peculiar construction and arrangement of the waterevaporating pan in the hot-air chamber for hydratin g the air passing up through the same. The fourth part of my invention relates to the peculiar arrangement of the radiating-surfaces and the smoke-passages, whereby a direct upward iiow is secured for the air-currents, while the heated currents of the products of combustion can be reverted, so as to pass in contact with the radiating-surfaces, and yield up the largest practicable percentage of their calorie; and in the general arrangement of the various parts, as more fully hereinafter set forth.

Figure 1, Sheet 1, is a longitudinal vertical section through the center of the furnace. Fig. 2 is a sectional plan on the two planes y yand z z. Fig. 3 is a transverse' vertical section through the center of the furnace at right angles with the section, Fig. 1. Fig. 4 is a horizontal section on the two planes m and w in Figs. l and 3. Fig. 5 is a perspective View of the furnace with a portion of the casing broken away. Fig. 6 is a horizontal section on the plane c c in Figs. l and 3, showing the evaporating-pan in plan. Fig. 7 is a vertical section of the smoke-pipe with the revertible draftdamper and a portion of the furnace.

In the drawing, A represents my fire-pot, into which coal is discharged by an inclined magazine or chute, A1, having a door over its end, which projects through the casing. This chute forms a hood, which incloses the entire top of the re-pot. B is a cast-iron air-pipe, which is transversely passed through the center of thecasing, from side to side, in a horizontal plane, passing through the furnace at the plane of the top of the fire-pot. The posterior part of the pipe is perforated over the irepot with a line of small air-holes, a, through which jets of air in a heated state enter the combustion-chamber and mingle with the gases evolved from the coal with which they mingle, and thus afford the oxygen necessary to secure their perfect combustion. A diaphragm, A2, extends from the top of the chute to the front of the pipe B. All that part behind this partition I term the combustion-chamber. C is the grate, and D is the ash-pit. In the back part of the ire-pot is a horizontal slot, b, about mid-height, through which the products of combustion issue. The fire-pot is oval, with the long diameter from front to rear. From the slot or throat b the heated currents pass up a flue, E, into a shallow circular chamber, F, owing across which they divide and pass down through two side drop-dues, G, into a circular fine, H, surrounding' the fire-pot, finding an exit through the vertical smoke-pipe l outside the casing Q. Direct draft is had by opening the damper c in the branch pipe I', connecting the chamber F with the pipe I. The lower end of the pipe I is provided with a check-door, d, by opening which the draft into the said pipe is decreased at will to regulate the combustion. The space between the combustion-chamber and the bottom of the chamber F forms a large air-chamber, the air in which, being partially heated by passing in contact with the annular iiue H, fire-pot, and

combustion-chamber, rises through a series of' tubes, P, passing vertically through both heads of the chamber F, where itis still furtherheated bythe heated air-currents flowingaround these tubes in their passage through the said fluechamber F, and collecting in the dome of the casing, whence it is taken by the air-ducts R to the apartments to be warmed. Upon the due-chamber, and surrounding the tops of the flue-openings, rests an annular waterpan, S, which has a spout, S', projecting through the casing for convenience in filling it with water whenever required. Fresh air is supplied to complished in the manner indicated.

capped openings, through which the flue-cham-.

the fuel through a register in the ash-pit door. The base-plate at the bottom of the shell is perforated with a series of radial slots, and under it a circular register, M, is pivoted thereto by a bolt through the center. The coldair duct should be so arranged as to deliver the supply of external air to the base-chamber below the base-plate. Ml is a ring-register around the lower part of the casing, which is perforated at regular intervals, as is the register. The registers M M/ are so attached to a single lever, e, as that, if the openings in the base-plate are disclosed, those in the casing will be closed, and vice versa. Ordinarily the air-supply will be drawn through the trunk and base-plate register; but in very cold weather it may be desirable to take the airsupply during the night from the room in which the furnace is placed, which can be ac- T T are ber and annular flue H may be cleansed of any deposits of soot and ashes.

It is well known that the furnaces heretofore constructed have utilized but a small percentage of the available heat in the fuel consu med, owing to the incomplete combustion of the gases evolved from the fuel, which become free as soon as the coal is heated, but will not ignite without the admixture of a proper volume of oxygen; hence the practice of admitting jets of air to the gases, which enables a portion of these gases to be ignited; but it is essential that the gases have, after the admixture of the oxygen, the space and an opportunity to ignite While at the proper temperature, for if they become cooled they will not ignite; hence the space above my fire-pot is divided into two compartments, the first of which receives the fuel, while the rear one forms the combustion-chamber, into which the heated air-j ets enter and mingle with the gases, which must pass over the incandescent fuel before passing out at the throat b into the flue, which insures the ignition and combustion of the gases. In this connection it will be noticed that the throat is below the plane of the bottom of the pipe B, forming an angle or slope, which should be the same as that at which coal will slide when taken from the lower outer edge of a pile.

The gases evolved from the coal collect in the combustionchamber, where the necessary volume of oxygen is admitted through the perforations a in the pipe B in a heated state, the ignition of the gases taking place as soon as they are heated to the proper temperature, which cannot be delayed long in passing over the incandescent mass at the back of the repot, which is the hottest, for the reason that it is of less thickness there, and offers less resistance to the draft. The coal at the front of the fire-pot does not burn, but smolders, until it rolls back to supply the place of a portion burned away near the throat.

What I claim as my invention, and desire to secure by Letters Patent, is

1. In a hot-air furnace, the combination of the fire-pot A, the chute A1, extending entirely across the saine, and the transverse diaphragm A2, all constructed and arranged substantially as described and shown.

2. In a hot-air furnace, the combination of the fire-pot A, the chute A1, extending diagonally entirely across the same, the transverse diaphragm A2, and the transverse air-pipe B, all constructed and arranged substantially asy described and shown.

3. In a hot-air-furnace, the annular evaporatiug-pan S, with a projecting spout, S', constructed and arranged substantially as described and shown.

4. In a hot-air furnace, the combination of the disk-register M, the ring-register M', and the lever e, the several parts being constructed and arranged substantially as described and shown.

WILLIAM H. LOTZ.

Witnesses THEO. KARLS, GEO. FROMMANN. 

